A bijection involving one-parameter families of strongly continuous functions with this property is given by Stone’s theorem. The existence of a projective (15[1])representation of the Poincaré group with this property is one of the Wightman axioms. This is the shorter-named of two properties that an operator can have to be compatible with a symmetry transformation on a Hilbert space by Wigner’s theorem. This property is held by operators of the form (*) e to the negative (10[1])“i times t over (10[1])h-bar (10[1])times a Hamiltonian”, (10[1])such (10[1])as a state’s (10[1])time-evolution (10[1])operator. Quantum gates (10[1])can be represented (10[1])by matrices (10[1])with this property, (10[2]-5[1])which is (10[1])the complex-valued (-5[1])equivalent of orthogonality. (-5[1])Matrices (-5[1])with (10[1]-5[1])this property preserve inner products and satisfy the equation “M*M (“M-star M”) equals the identity.” (-5[1])For 10 points, name this (-5[1])property of matrices in the group U(n) ■END■ (10[2]0[5])